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The taxonomy of the rhodolith-forming species of non-geniculate coralline algae from the subfamilies Neogoniolithoideae and Hydrolithoideae (Rhodophyta, Corallinales) found from Espírito Santo State, Brazil, was evaluated based on extensive subtidal sampling. A comparative analysis of the Brazilian material to other recently described species lead us to conclude that one relatively well-known species, namely Hydrolithon rupestre, a conferatum species Neogoniolithon cf. brassica-florida and a probably new species of the genus Hydrolithon, are present in the area. All three species can be distinguished by their tetrasporangial or gametangial conceptacle anatomy. This study strengthens the hypothesis that Brazilian rhodolith beds are comparatively more diverse in numbers of rhodolith-forming species than other areas of the world.

The Late Miocene Malbusca outcrop is located in the southeastern coast of Santa Maria Island (Azores, NE Atlantic), interspersed in volcanic formations. At ~20 meters above present sea level, a prominent discontinuous layer of rhodoliths seizes with an extension of ~250 meters. This paper presents the first taxonomic record of fossil rhodolith forming coralline algae for the Miocene of the Azores. The preserved taxonomic features used were the following: (1) arrangement of basal filaments, (2) epithallial cells (when observable), (3) presence of cell fusions, (4) conceptacle type, (5) number of cells layers which conceptacle chamber floors are situated below the surrounding thallus surface and (6) for the sporangial pores, the orientation of the filaments around the conceptacle pores. Based on these characters, six taxa were identified encompassing three Corallinaceae (Lithophyllum prototypum, Lithophyllum sp., Spongites sp. and Hydrolithon sp.) and one Hapalidaceae (Phymatolithon calcareum and cf. Phymatolithon sp.). An unidentified coaxial thallus was also present, the coaxial construction ascribing the specimens to the genus Mesophyllum or Neogoniolithon. Taxonomic accounts for the identified taxa are described, illustrated and an identification key is provided. The report of L. prototypum represents the first Miocene record and the preservation of the specimens is very good. Miocene coralline algae seem very consistent among deposits but some species are relevant for particular areas, like in the Azores.

This is the first revision of Neogoniolithon species on the east coast of Mexico based on both DNA sequences ( psb A) and morpho-anatomical characters. Nine species names are provisionally applied based on morpho-anatomical comparisons with type specimens or with species descriptions: N. accretum , N. acropetum , N. erosum , N. mamillare , N. propinquum, N. rhizophorae, N. solubile , N. spectabile and N. strictum . For none of these species was type or topotype material sequenced, but all have their type localities in the subtropical or tropical western Atlantic Ocean. Neogoniolithon siankanensis is described on the basis of a distinctive branched thallus, apical tetrasporangial conceptacles and DNA sequence. Another four species are present, each characterized by DNA sequence, but insufficient reproductive material was available to adequately describe these species. A suite of vegetative and reproductive characters can adequately segregate the currently named Mexican east coast Neogoniolithon species, including 1) branched versus unbranched thalli, 2) monomerous versus dimerous construction, 3) disposition of trichocytes, 4) interior dimensions of mature tetrasporangial conceptacles, 5) number of cell layers comprising tetrasporangial conceptacle roof and 6) shape of cells that line tetrasporangial pore canal. Morpho-anatomical descriptions and distributions are provided for all named species.